X-ray detector on 2U cubesat BeEagleSAT of QB50

BeEagleSAT is a 2 Unit cubesat to be launched within the EU FP7 project QB 50. It is been produced by Istanbul Technical University and Turkish Air Force Academy. Sabanci University will provide a CdZnTe based semiconductor X-ray detector and associated readout electronics. The detector will utilize cross strip geometry to test the detection system in space, but it will not carry a mask for imaging. The readout will be established by an application specific integrated circuit controlled by a microcontroller. The system will have its own battery and will be turned on intermittently due to power and telemetry constraints. It will characterize the hard X-ray background in 20-150 keV at low Earth orbit conditions as a function of altitude

Linear position-sensitive x-ray detector incorporating a self-scanning photodiode array

A linear position-sensitive x-ray detector for x-ray spectroscopy and diffraction applications has been tested which can provide excellent spatial resolution, wide dynamic range and good sensitivity. The heart of the system is a self-scanning, photosensitive silicon diode array. It is interfaced via fiber optics to a thin layer of ZnS which fluoresces visible light upon absorption of x-radiation. The conversion to visible light and optical coupling provide several-fold gain in the efficiency of detection as compared to the direct detection of x-ray by the diode array. Equally important is that the array is protected from irreversible damage by high energy radiation, a limitation which previously hindered this application of silicon diode technology

High Resolution X-Ray Spectroscopy with Compound Semiconductor Detectors and Digital Pulse Processing Systems

The advent of semiconductor detectors has revolutionized the broad field of X-ray spectroscopy. Semiconductor detectors, originally developed for particle physics, are now widely used for X-ray spectroscopy in a large variety of fields, as X-ray fluorescence analysis, X-ray astronomy and diagnostic medicine. The success of semiconductor detectors is due to several unique properties that are not available with other types of detectors: the excellent energy resolution, the high detection efficiency and the possibility of development of compact detection systems. Among the semiconductors, silicon (Si) detectors are the key detectors in the soft X-ray band (< 15 keV). Si-PIN diode detectors and silicon drift detectors (SDDs), with moderate cooling by means of small Peltier cells, show excellent spectroscopic performance and good detection efficiency below 15 keV. Germanium (Ge) detectors are unsurpassed for high resolution spectroscopy in the hard X-ray energy band (>15 keV) and will continue to be the choice for laboratory-based high performance spectrometers. However, there has been a continuing desire for ambient temperature and compact detectors with the portability and convenience of a scintillator but with a significant improvement in resolution. To this end, numerous high-Z and wide band gap compound semiconductors have been exploited. Among the compound semiconductors, cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) are very appealing for hard X-ray detectors and are widely used for the development of spectrometer prototypes for medical and astrophysical applications. Beside the detector, the readout electronics also plays a key role in the development of high resolution spectrometers. Recently, many research groups have been involved in the design and development of high resolution spectrometers based on semiconductor detectors and on digital pulse processing (DPP) techniques. Due to their lower dead time, higher stability and flexibility, digital systems, based on directly digitizing and processing of detector signals (preamplifier output signals), have recently been favored over analog electronics ensuring high performance in both low and high counting rate environments. In this chapter, we review the research activities of our group in the development of high throughput and high resolution X-ray spectrometers based on compound semiconductor detectors and DPP systems. First, we briefly describe the physical properties and the signal formation in semiconductor detectors for X-ray spectroscopy. Second, we introduce the main properties and critical issues of a X-ray detection system, highlighting the characteristics of both analog and digital approaches. Finally, we report on the spectroscopic performance of a high resolution spectrometer based on a CdTe detector and a custom DPP system. As an application, direct measurements of mammographic X-ray spectra by using the digital CdTe detection system are also presented

PENERAPAN HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) PADA PROSES PRODUKSI WAFER ROLL [Implementation of Hazard Analysis and Critical Control Point (HACCP) in Production of Wafer Roll]

The purpose of this study was to determine the application of Hazard Analysis and Critical Control Points (HACCP) to identify and prevent potential hazards in the production process of chocolate roll wafers at PT. X.  The production process of wafer roll at PT. X consisted of mixing raw materials, filtering, roasting, rolling a wafer roll, filling cream, cutting, decreasing wafer roll temperature, packaging, and X-ray detection.  The implementation of a quality assurance system must be carried out at every stage of processes to prevent microbiological chemical, and physical hazard pollution, and maintaining product quality.  The study was conducted using a survey method, by directly following the entire process of making chocolate roll wafers from the receiving of raw materials to the final product in the packaging.  The data was analyzed using descriptive analysis method.  The application of the HACCP system at PT. X through two steps, that were preliminary hazard analysis step and hazard analysis step.  The results showed that the X-ray detection pathway found CCP contamination of foreign objects with significant hazards in the form of metal parts in the product.  Preventive actions taken included separating and marking deviant products, repairing the auto stop system, and visual observation by employees on X-ray detection machines

Studies on neutron diffraction and X-ray radiography for material inspection

Among the different probes to study the structures of the bio and structural materials, X-ray and neutron are widely used because of their distinctive usefulness in investigating different structures. X-ray radiography and neutron diffraction are two widely known non-destructive techniques for material inspection. Here we demonstrate the design of neutron diffractometer with low power source and analyze the digital image produced by the X-ray radiography instead of neutron diffraction because of the availability of the data. Neutron diffraction is a powerful tool for understanding the behavior of crystal structures and phase behaviors of materials. While neutron diffraction capabilities continue to explore new frontiers of materials science, such capabilities currently exist in limited places, which require high neutron flux. The study seeks to design a low-resolution neutron diffraction system that can be installed on low power reactors (e.g. 250 kW thermal power). The performance of the diffractometer is estimated using Monte-Carlo ray-tracing simulations with McStas with an application in material science. Both monochromatic and polychromatic configurations are considered in order to maximize the net diffracted neutron flux at the detectors with reasonable resolution. On the other hand, considering X-ray radiography as a structure inspecting technique, analysis of dental X-ray panorama is performed for the detection of oral lesions. A novel automatic computer-aided method to identify dental lesions from dental X-ray is presented. Morphological operations, intensity profile analysis, automated seed point selection, region growing, feature extraction and neural network application are carried out to perform the job. Results show that the performance of the proposed method surpasses existing automated methods utilizing dental X-rays --Abstract, page iii

The Electron Microscope Detection and X-Ray Quantitation of Cations in Bacterial Cells

Electron microscope autoradiography and X-ray microanalysis have been used for the detection and quantitation of cations in the bacterium Pseudomonas tabaci. These techniques differ in the information they provide (relating to either cation uptake or in situ levels), their applicability to different cations, their sensitivity and their spatial resolution. With uptake of 63Ni2+, high resolution autoradiography (involving gold latensification and physical development) demonstrated a high degree of cation localisation to the central nucleoid area (glutaraldehyde-fixed cells) and within this to the constituent chromatin (acetic-alcohol preparations). X-ray microanalysis of whole bacterial cells revealed the presence of substantial levels of K (mainly soluble cation}, Ca, Mn, Ni, Cu and Zn (mainly in soluble cations) and Fe (present as major soluble and insoluble components). The use of whole cells provided a particularly useful experimental system to demonstrate the importance of cell preparation technique in relation to element detectability. The application of X-ray microanalysis to lysed cells permitted analysis of extruded contents -including cell protoplast (protoplasm without associated cell wall material) and chromatin fibrils. The microprobe detection of DNA-associated cations was most effective with freshly extracted chromatin and showed the presence of bound K, Ca and transition metals

X-Ray Image Processing and Visualization for Remote Assistance of Airport Luggage Screeners

X-ray technology is widely used for airport luggage inspection nowadays. However, the ever-increasing sophistication of threat-concealment measures and types of threats, together with the natural complexity, inherent to the content of each individual luggage make x-ray raw images obtained directly from inspection systems unsuitable to clearly show various luggage and threat items, particularly low-density objects, which poses a great challenge for airport screeners. This thesis presents efforts spent in improving the rate of threat detection using image processing and visualization technologies. The principles of x-ray imaging for airport luggage inspection and the characteristics of single-energy and dual-energy x-ray data are first introduced. The image processing and visualization algorithms, selected and proposed for improving single energy and dual energy x-ray images, are then presented in four categories: (1) gray-level enhancement, (2) image segmentation, (3) pseudo coloring, and (4) image fusion. The major contributions of this research include identification of optimum combinations of common segmentation and enhancement methods, HSI based color-coding approaches and dual-energy image fusion algorithms —spatial information-based and wavelet-based image fusions. Experimental results generated with these image processing and visualization algorithms are shown and compared. Objective image quality measures are also explored in an effort to reduce the overhead of human subjective assessments and to provide more reliable evaluation results. Two application software are developed − an x-ray image processing application (XIP) and a wireless tablet PC-based remote supervision system (RSS). In XIP, we implemented in a user-friendly GUI the preceding image processing and visualization algorithms. In RSS, we ported available image processing and visualization methods to a wireless mobile supervisory station for screener assistance and supervision. Quantitative and on-site qualitative evaluations for various processed and fused x-ray luggage images demonstrate that using the proposed algorithms of image processing and visualization constitutes an effective and feasible means for improving airport luggage inspection